Primary open angle glaucoma (POAG) is a leading cause of blindness. This disease disproportionately affects African Americans, who have a four- to five-fold higher risk of disease than age-matched Caucasians. In addition to its high prevalence, the risk of blindness from glaucoma in African Americans is more than 10 times greater than Caucasians, making it the leading cause of blindness in African Americans. The goal of this study is to identify common genes that are responsible for idiopathic Primary Open Angle Glaucoma in the understudied African American population. Whole genome association (WGA) has recently met with dramatic success in the analysis of complex diseases, including the identification of Complement Factor H as the strongest genetic risk factor for age- related macular degeneration. These methods typically utilize hundreds of thousands of genetic markers to conduct case-control association tests on genes across the entire human genome. These methods have not been applied to glaucoma in African Americans because of the extremely high cost, and because of the difficulty of assembling the necessary dataset: historical research abuses have made many potential African American controls reluctant to participate in medical research. Both of these difficulties can be addressed through the use of a new whole genome association technique call admixture mapping. Admixture mapping is a whole-genome association technique that takes advantage of the unique genetic structure of admixed populations such as African Americans. It has recently been used to successfully map genes for multiple sclerosis and prostate cancer. Admixture mapping is 4-5 times less expensive per sample than other forms of whole-genome association because it requires many fewer markers while retaining similar power to detect disease-associated susceptibility variants. Further, this technique uses only African American cases and does not require matching controls, thus enabling a highly powered initial genome scan. Follow-up to the genome scan will be performed in a large POAG case/control dataset collected in Ghana, West Africa. The identification of glaucoma susceptibility genes in African Americans could lead to improved treatment methods for this severely affected and understudied population. PUBLIC HEALTH RELEVANCE Glaucoma is especially common and severe in African Americans. We are using a new genetic technique to find genes that contribute to glaucoma in this population. Finding such genes could prevent blindness by leading to better treatments for the disease.